1989 325i Slow idle - United Bimmer Community

**jfergt** · 05-09-2008, 09:45 AM

I have a 1989 325i and recently it has developed a slow idle. When I break or lift off the accelerator the rpm drops off quickly to near 500, the car almost stalls and then the rpm returns to around 700.

Does anyone have any suggestions as what the most likely cause of this is?

Also, my speedometer isnt working as a cable has corroded near the diff. I dont believe the speed sensor on the diff provides any control function.

All help appreciated

Thanks

jfergt

**94bmw325i** · 05-09-2008, 02:28 PM

checked to see if you have any loose vacuum lines? They might have dry rotted also.

**elsabor67** · 05-10-2008, 11:15 AM

I would check the vacuum hoses too. Also check and see what condition is the speed sensor. The cables on it are not that hard to repair.

**Gigarod** · 05-10-2008, 08:15 PM

Thanks guys,

Checked and changed most vacuum hoses.

Will check the speed sensor (I have to do something... ).

On another note:
I took a good look under the dash (took of glove box, console, heater part of the dash) did not find an Idle Control Module. (Car was built 12/87, it's an 88).

Thanks for the info, speed sensor is the next on the list!
(Will check the forum for some information about it; where it is, what it looks like, taking it off, checking it, putting it back on...).

Beauty is in the eye of the beer holder.

**elsabor67** · 05-11-2008, 11:11 AM

Quote:

Originally Posted by Gigarod

Thanks guys,

Thanks for the info, speed sensor is the next on the list!
(Will check the forum for some information about it; where it is, what it looks like, taking it off, checking it, putting it back on...).

Beauty is in the eye of the beer holder.

The sensor is on the back of your diff from where the cables come from. The only non fun part is the tracing back to the dash. But the sensor itself isn't that hard.